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CVE-2026-50202
medium
CVSS 5.9
Vulnerability in Steeltoe.Security.Authentication.JwtBearer (CVE-2026-50202)
Summary
vulnerability in Steeltoe.Security.Authentication.JwtBearer (CVE-2026-50202). Confidential information can be exposed externally. Exploitable via ``TokenKeyResolver``. Mitigation: upgrade to `4.2.0` or later.
AI summary snake-internal / snake-material-v2
A vulnerability tracked as **CVE-2026-50202** has been found in Steeltoe.Security.Authentication.JwtBearer.
Attackers can target a specific entry point like ``TokenKeyResolver`` over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 5.9/10.
What to do: upgrade Steeltoe.Security.Authentication.JwtBearer to **4.2.0** or later.
If unsure, ask your IT team or search "Steeltoe.Security.Authentication.JwtBearer CVE-2026-50202" on the vendor's site.
CVE-2026-50202 (Steeltoe.Security.Authentication.JwtBearer) — CWE-668 / CVSS v3 5.9
Attack vector: remote (network-reachable) / no user interaction
Attack surface: `TokenKeyResolver` / `kid` / `JwtBearer`
Patched: `4.2.0` — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
❓ What is the problem
**A vulnerability** (CWE-668) exists in Steeltoe.Security.Authentication.JwtBearer. Attackers reach the vulnerable code path via ``TokenKeyResolver`` without authentication.
📍 Affected scope
Steeltoe.Security.Authentication.JwtBearer — . Attack surface: `TokenKeyResolver` / `kid` / `JwtBearer`.
🔥 Severity
Severity: Medium (CVSS 5.9/10). Confidential information can be exposed externally
🔧 How to fix
Update to **4.2.0**.
🛡️ Workaround
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
🔍 Detection
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run `grep -r 'Steeltoe.Security.Authentication.JwtBearer' .` against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response Actions (7 steps)
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
grep -r 'Steeltoe.Security.Authentication.JwtBearer' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で `Steeltoe.Security.Authentication.JwtBearer` を grep し、稼働しているサービス・バージョンを把握する。
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6Apply patch patch
Upgrade Steeltoe.Security.Authentication.JwtBearer to 4.2.0ステージング環境で 4.2.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスと、Step 3 で見つけた異常検知の続報チェックを含めること。
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7Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 3 と同じログクエリでアラート再発が無いか継続監視。
Affected packages
nuget
Steeltoe.Security.Authentication.JwtBearer
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.2.0"}]}]
nuget
Steeltoe.Security.Authentication.OpenIdConnect
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.2.0"}]}]
nuget
Steeltoe.Security.Authentication.CloudFoundryBase
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.4.0"}]}]
References
- web https://github.com/SteeltoeOSS/Steeltoe/commit/04db2ace3b806bfe0260bb7d4bda340f241eff48
- web https://github.com/SteeltoeOSS/Steeltoe/commit/17b27b8be546ae3f83a2f6e91d45e0c84c5314b7
- web https://github.com/SteeltoeOSS/security-advisories/security/advisories/GHSA-7fqc-p256-7pwj
- web https://nvd.nist.gov/vuln/detail/CVE-2026-50202
- web https://github.com/advisories/GHSA-7fqc-p256-7pwj